Tumbleweed Whenever you think of the Wild West of America, you think of cowboy movies and tumbleweed, perpetually tumbling around a desolate landscape.
Salt lowers the freezing/melting point of water, so in both cases the idea is to take advantage of the lower melting point. Ice forms when theÂ­ temperature of water reaches 32 degrees Fahrenheit (0 degrees Celsius). When you add salt, that temperature drops: A 10-percent salt solution freezes at 20 F (-6 C), and a 20-percent solution freezes at 2 F (-16 C). On a roadway, this means that if you sprinkle salt on the ice, you can melt it. The salt dissolves into the liquid water in the ice and lowers its freezing point.
At that temperature, the salt begins to crystallize out of solution (as NaClÂ·2 H2O), along with the ice, until the solution completely freezes. The frozen solution is a mixture of separate NaClÂ·2H2O crystals and ice crystals, not a homogeneous mixture of salt and water.hat's why salt melts ice. To re-establish equilibrium, you must cool the ice-saltwater mixture to below the usual melting point of water. For example, the freezing point of a 1 M NaCl solution is roughly -3.4Â°C. Solutions will always have such a freezing point depression.